"We should be talking about emissions targets, and the right emission target is zero."(Ken Caldeira climate expert Stanford​)

"I asked the top scientists on this several times: Do we really have to get down to near zero? Can't we just cut it in half or a quarter? And the answer is that until we get near to zero, the temperature will continue to rise." (Bill Gates)

'These [mitigation] pathways would require substantial emissions reductions over the next few decades and near zero emissions of carbon dioxide and other long-lived greenhouse gases by the end of the century'. (IPCC 2014 AR5 Headline Statements)

'Without mitigation policies, fossil fuel and industrial emissions could reach 55-70 GtCO2 by 2050 and around 90 GtCO2 by 2100. This is in stark contrast with a low carbon future, where the energy system needs to be virtually zero carbon by 2100' (PwC Briefing: IPCC Fifth Assessment Report (AR5) Working Group III – Mitigation of Climate Change April 2014)

‘...pathways (for mitigation)... would require substantial emissions reductions ... and near zero emissions of carbon dioxide and other long-lived greenhouse gases by the end of the century.’ (IPCC AR5 20014 SYN SPM Headline Statements

​CO2 is the top cause of global warming and the cause of ​ocean acidification.​​Black carbon (soot) is second only to CO2 ​in global warming contribution, ​so zero carbon now appropriately means zero CO2 and zero black carbon.

IPCC 2014 AR5​ .. near zero emissions of carbon dioxide by the end of the century.